1. Field of the Invention
The present invention relates to a bar code input device typically having an optical scan element that can be worn on the back of the hand allowing the user to scan a bar code symbol by simply pressing a finger at the base of the bar code symbol.
2. Description of Related Art
Optical readers and optical scanning devices have been developed for reading bar code symbols. A bar code symbol represents a common one-dimensional form of symbology, and comprises a pattern of vertical bars of various widths separated by spaces of various widths. Since the bar and space elements have different light reflecting characteristics, a reader can convert the symbology into an electrical signal by analyzing the light reflected from the symbol. The electrical signal can then be decoded to provide an alphanumeric representation of the symbol that identifies the object. Bar code symbols of this nature are now in common usage in various applications, such as inventory control, point of sale identification, or logistical tracking systems.
Many applications of the bar code readers require the operator to move about the readers and carry them from place to place. Thus, the readers must be easy to carry and operate. Hand-held devices have been developed to allow a user to aim the reader at a target bar code to be read. A problem with this type of reader is that the user is frequently a worker that is periodically entering data on a keyboard or performing several manual tasks with his hands related to the general work being undertaken. Traditional hand-held bar code readers have required intermittently setting down the device to perform other manual tasks, or switching to the other hand to facilitate the use of the hand for other operations.
As a result, several bar code readers have been adapted to be worn on the back of a user's hand. One type of hand-mounted device disclosed in U.S. Pat. No. 5,514,861 to Swartz, et al. is activated by pressing a button with the thumb. A drawback of the device is that the thumb must be bent in an awkward way to activate the button. Another hand-mounted device disclosed in U.S. Patent No. 5,340,972 to Sandor is activated by flexing the fingers. The operator activates the bar code scan element by raising, extending and pointing his finger at the bar code and keeping it flexed until the operator desires to deactivate the reader. This device is also undesirable because the bar code scan element is activated when both the index finger and the middle finger are in relaxed nonpointing positions followed by a pointing position of the index finger and the simultaneous relaxed nonpointing position of the middle finger. The user must consciously relax the fingers other than the index finger to activate the scan element. Another hand-mounted device disclosed in U.S. Pat. No. 4,766,299 to Tierney, et al. is activated by flexing the hand in a certain fashion to be detected by the device. The switch is activated by deliberate flexure of the muscles in the hand such as clenching the hand into a fist or pointing a finger in the direction of the bar code. Thus, these types of readers require unnatural movements of the hand to actuate the scan element.
Another significant drawback of conventional hand-mounted readers is that they have complex optical systems that add bulk and high scan element costs. The scan element may include a laser scanning device mounted in a housing such that a laser is aimed in the direction of the bar code. These laser scanning systems generally comprise complicated systems such as lenses and mirrors to read a bar code symbol, thus increasing the bulk and expense of such systems.
Conventional hand-mounted bar code readers have another drawback in that they generally include an integrated glove that incorporates a scan element in a housing that is often bulky and sits high on the hand or finger. Some users may be required to use additional gloves such as protective gloves for lifting inventory. Bulky conventional gloves incorporating the scan element can only be worn on a bare hand and would preclude the user from wearing any other type of glove.
Accordingly, a need exists for a low cost, low complexity hand-mounted bar code reader that allows a user to scan bar codes with a natural motion and to wear it on a bare or gloved hand.